"Blend from shape" What does this do? how can I use it?
One very common use is to repair a shape key from a mistake, while leaving the desired deformations intact: if you like your shape key but you see some moving vertices that should stay still, you can select them, choose blend from shape, pointing at the basis shape, unchecking the &quot;add&quot; option (so to replace the moving vertices informations with the basis static locations).